This invention relates to the novel configuration of a collapsible, or deployable, truss unit and to frameworks composed of a plurality or multiplicity of such truss units joined together in a series or in rows and columns. The truss units in accordance with the invention are well suited for the construction of medium to large scale structures in outer space, as well as of temporary or emergency structures on the earth, among other applications.
With the rapid development in recent years of space technology, the exploration and utilization of outer space is becoming, and to a certain extent has become, a matter of reality. Space engineers envisage such structures in orbit as space colonies, space stations, solar power plants, huge antennas, etc. All the building materials for such orbiting structures must of course be transported from the earth. Thus the building materials for space use must meet the following requirements:
1. Maximum possible lightness.
2. Smallness in size--small enough to be loaded on launch vehicles or space shuttles.
3. Ability to be closely packed together during transportions.
4. Ease of construction or assemblage in space.
5. High rigidity of the framework constructed.
Many space specialits agree that trusses fulfill all these requirements and are the most promising building materials for the frameworks of large space constructions. Nestable columns are an example of such building materials heretofore suggested, with an emphasis on compactness during transportation. However, supposedly, it will be no easy task to construct any desired structure in space from such discrete truss members. Construction work may be automated and done by robots but may still demand human assistance, even at the risk of life.
Deployable truss structures represent a solution to this problem. Even though they cannot possibly be nested so compactly as the individual truss members during shipment, the deployable truss structures can be automatically or semiautomatically unfolded into shape in space. Several such truss structures are known, most of them being extensible in one direction only. An example is found in Japanese Patent Publication No. 49-26653. This and other similar conventional truss structures are collapsed by bending some constituent members in the middle.
Two dimensionally deployable trusses have also been suggested, an example being disclosed in "Status of Deployable GEO-TRUSS Development" by J. A. Fager in NASA CP-2269 Part 1, "Large Space Antenna Systems Technology", published 1982. The "Geo-Trusses" when deployed make up a planar or curved array of approximately regular tetrahedral units and approximately regular octahedral units. For collapsing this structure, all the truss members on its opposite surfaces must be bent in the middle.